Silicon nanocrystals - a luminescence convertor applied to silicon solar cells

In this contribution we investigate an implementation of silicon nanocrystals (Si-nc) into photovoltaic in order to improve the performance of the solar cells. The Si-nc are prepared ex-situ from porous silicon and embedded into SiO/sub 2/ based spin-on-glasses (SOG) layers and deposited on standard silicon solar cell. We are presenting the photo luminescence properties of such a SOG/Si-nc layers. When such a thin film layer is deposited on the top of the silicon solar cell it behaves as a luminescence converter. The high energetic photons are absorbed by the silicon nanocrystals and transformed via luminescence mainly to red ones. The lost of these high energy photons by thermalization is therefore strongly reduced. An improvement in the spectral response at the region where the Si-nc photoluminescence excitation occurred is observed. This enhancement is due to increased carrier collections via the luminescence converter. We present the correlations between the PL of such a converter based on Si-nc and the internal quantum efficiency. When the photoluminescence of Si-nc decreases an increase in the spectral response in the region where the Si-nc excitation appears is recorded. The association of silicon nanocrystals, spin-on-glass layers and silicon based cells is promising to improve the efficiency at low-cost.